1997 K11 idles weird sometimes

[stavroskltz]

Hello! I got a 1.0L 1997 K11 from my grandpa which was in need of a full service. I have changed everything on it, and took it for a test drive today. While driving it i noticed something weird. First off, the car has terrible pre ignition issues. For example, whenever i press the accelerator pedal more than 20% and put some load on the engine, the engine pre ignitions a lot. Although this might be because of old gasoline that is in the tank. The main problem i am more concerned about, is that the rpm's don't immediately drop (rev hangs) after every gear change. Also sometimes, whenever i put neutral when coming to a red light, the engine will stay running at high rpm and won't drop to 900-1000 rpm after 2-3 seconds. In some cases it will actually idle at 2000 rpm without dropping at all. When it idles at 2000rpm i turn the engine off, and the turn it back on and it will idle fine. What could the issue be? maybe a dirty MAF sensor? (air filter hadn't been changed in years) Was thinking on cleaning it, but on prefacelift micras i cant remove the MAF sensor from the throttle body housing. Any help appreciated! Thanks!

 

[.Maarten]

I would start with cleaning the throttlebody and idle air valve. And check the throttle cable to see if its not sticking

 

[stavroskltz]

I would start with cleaning the throttlebody and idle air valve. And check the throttle cable to see if its not sticking

I checked the throttle cable and it seemed pretty good to me to be honest. How do i clean the throttle body and idle air valve?

 

[.Maarten]

Remove the throttlebody and spray some throttlebody cleaner in it and wipe down with a rag. Watch out for the maf.
And the idle air valve can be cleaned the same way but do mark it and make sure it goes back on the same position

 

[stavroskltz]

Remove the throttlebody and spray some throttlebody cleaner in it and wipe down with a rag. Watch out for the maf.
And the idle air valve can be cleaned the same way but do mark it and make sure it goes back on the same position

I removed the whole throttle body assembly today. It had a lot of carbon build up.. I cleaned it thoroughly with a cleaner. I also removed the idle solenoid

(number 11) from the throttle body assembly and cleaned that aswell. I didnt touch the maf sensor at all. Bolted everything back on and took it for a test drive and unfortunately the problem is still there but it is a bit better. The idle still needs 2-3 seconds to drop, but hey atleast it drops while previously it would sometimes hold the idle at around 2k rpm without dropping. Idk what to do next... Maybe the ECU needs some relearning or something? Car hadnt started in months and battery was dead. So there were a lot of times where i disconnected the battery on the car, and maybe i have to just use the car without disconnecting the battery for a good period of time, so i can let the ECU do it's thing?

 

[.Maarten]

You can try removing part 10,12 and 14. Those are for the waxstat that holds the throttle open when cold. But they tend to seize up after years and can cause the throttlevalve to stay open a bit.

And check for vacuum leaks.

 

[stavroskltz]

You can try removing part 10,12 and 14. Those are for the waxstat that holds the throttle open when cold. But they tend to seize up after years and can cause the throttlevalve to stay open a bit.

And check for vacuum leaks.

Alright. Is it possible to grease these parts with a silicone spray for example? Or I shouldnt do that. Also, I checked for any cracked hoses that go to the throttle body, but 2 hoses have water in them, and the 3rd one (going from the throttle body to the charcoal canister) was a bit cracked so I cut it and re installed it but nothing really changed. Are there any vacuum hoses that go to the inlet manifold itself that i should check?

 

[.Maarten]

There is a vacuum hose going from the inlet to the fuel pressure regulator and that one sees more heat and it wouldnt be the first one that goes bad. Also you dont need the wax stat and silicone spray wont do anything as its the wax in part 9 that goes bad so that the plunger in part 9 doesnt move or doesnt move enough. Removing part 10,12 and 14 disables that system.

 

[stavroskltz]

There is a vacuum hose going from the inlet to the fuel pressure regulator and that one sees more heat and it wouldnt be the first one that goes bad. Also you dont need the wax stat and silicone spray wont do anything as its the wax in part 9 that goes bad so that the plunger in part 9 doesnt move or doesnt move enough. Removing part 10,12 and 14 disables that system.

alright, will have a check tomorrow. Thanks!